This invention relates to a storm water nutrient separating vault having an articulating floating filter basket for collecting debris entering the vault and especially to a swiveling floating filter basket supported in a storm water vault with a plurality of swiveling roller trucks riding on a pair of tracks mounted on each side of the storm water inlet to the storm water nutrient separating vault to support and guide the floating screen basket as it moves with the level of water in the vault.
The objective of the Nutrient Separating Baffle Box is to treat a storm drain pipe by capturing contaminates such as foliage, litter, and sediments, and lighter than water liquids such as petroleum products. During a rain event as water flows into the Nutrient Separating Baffle Box, floatables such as foliage and litter are captured in the screen system, and sediments which are heavier than water, settle in the lower baffled settling chambers. After the rain event is over the hydraulic grade line of the water in the Nutrient Separating Baffle Box lowers to a level that is even with the tops of the baffles which is below the bottom of the screen system. This allows for the captured debris in the screen system to dry out between rain events, and not allow the nutrients in the captured foliage to leach into the water and become food for bacterial growth. The result of removing pollutants from the storm water flow prevents the conveyance of these pollutants into downstream bodies of water such as lakes, rivers, streams, etc.
This process of treating the water flow can create headloss which could impede the flow and reduce the rate of flow. If the treatment results in a significant reduction in the rate of flow, it is possible for flooding to occur upstream from the storm water treatment structure. Minimizing the headloss caused by a treatment system is important, especially when a treatment system is retrofitted to an existing drain pipe.
The Nutrient Separating Baffle Box (NSBB) provides treatment with minimal headloss by providing a non-obstructed conveyance for water flow through the vault that is equal or greater than the cross-sectional area of the inflow pipe below the ceiling of the inflow pipe. In most applications, it is not practical to make use of a tall screen system that may block off water flow if the screen becomes obstructed. A floating screen system of limited vertical height would be able to move with the changing water level to capture floatables moving near the surface of the water.
If the screen system is relatively short compared to the pipe size to minimize head loss, the screen system could float up during large flows so that it remains in line with the water level while allowing water to bypass under the screen system. This would enable the screen system to continue capturing floatables throughout a high flowing rain event.
The screen system would be able to automatically move vertically with a changing water level that is influenced by tides. Tides along the coasts of the continental US vary as much as 11 feet, and many storm water outfall pipes are below the coastal water level for much of the time. If the storm water treatment system is adjacent to a lake, the screen system would be able to automatically move with the changing lake level. It is common for lake levels to vary significantly depending on the time of year.
Applicant's prior U.S. patents which involve filter baskets may be seen in U.S. Pat. No. 7,981,283 for an Adjustable Filter Basket for Storm Water Drain System which has a nutrient separating filter basket for a storm water drain pipe which adjusts the height of the filter basket manually for catching floating debris entering a catch basin. U.S. Pat. No. 7,153,417 is for a floating storm water drain basket which adjusts for the height of the water in a housing. A scoop formed on the front end of the filter basket is positioned to face the inlet to the housing for capturing floating debris entering the housing. Floats are attached to the filter basket to position the basket for varying water levels in the housing.
U.S. Pat. No. 7,846,327 teaches a Storm Water Filter System having a Floating Skimmer Apparatus for preventing floatable debris from entering a filter box outlet. The portable skimmer is positioned in the box between the inlet and outlet to the box and keeps the skimmer above the water level in the box to keep floating debris from entering the outlet from the box.
Applicant's patents which use floating weirs or skimmers include U.S. Pat. No. 8,034,236 for a storm water system having a floating skimmer apparatus attached in a storm water filter box and in U.S. Pat. No. 8,034,234 for a Floatable Skimmer Apparatus with Up-Flow Filter for filtering floatable debris and non-floating pollutants from storm water passing through a storm water drain system. U.S. Pat. No. 8,083,937 teaches a floatable baffle panel and filter apparatus for filtering floatable debris from storm water passing through a storm water drain system vault. A wall having a passageway therethrough has a filter passageway for filter the storm water and a floatable baffle panel covering a second passageway for capturing floatable debris and trash from the storm water. U.S. Pat. No. 8,231,780 is for a Floating Skimmer and Filter Apparatus for filtering floatable debris and non-floating pollutants from storm water passing through a drain system vault. A floatable skimmer has a filtered passageway filtering water passing through the passageway while the floatable skimmer captures floating debris and trash from the storm water.
Other U.S. patents of Applicant relating to storm water systems may be seen in U.S. Pat. No. 7,549,820 for a Curb Opening Filter and U.S. Pat. No. 7,785,464 for Flocculate Dosing Tray and U.S. Pat. No. 8,034,237 for Backwashing Filter Basket and U.S. Pat. No. 8,216,453 for Grate Cover Apparatus and U.S. Pat. No. 6,270,663 for Storm Drain Filter System and U.S. Pat. No. 6,428,692 for In-line Storm Water Drain Filter System and U.S. Pat. No. 6,869,525 for Storm Drain Filter System and U.S. Pat. No. 6,797,162 for a Catch Basin Filter for Storm water Runoff and U.S. Pat. No. 6,979,148 for Golf Course Green Storm Water Filter and U.S. Pat. No. 7,959,799 for a Street Curb Filter Basket System.